Automatically Locking and Tumbler Scrambling Manipulation Proof Lock

The present invention relates in general to manually operated combination locks having a plurality of tumbler wheels with associated tumbler wheel gates which must be aligned to operate the lock and more particularly to such a lock which is adapted to scramble the alignment of such tumbler wheels automatically in response to a locking motion of the associated lock bolt and bolt operating fence lever.

Manually operated combination locks are generally well known as disclosed in prior U.S. Pat. Nos. 4,541,259 entitled "COMBINATION LOCK" and U.S. Pat. No. 4,142,388 entitled "TUMBLER WHEELS FOR COMBINATION LOCKS" by way of example. It is common, in such locks, to provide a plurality of tumbler wheels having gates therein which must be aligned through manipulation of an associated lock dial and shaft associated with the tumbler wheels in order to allow a fence arm to enter the gates, the fence arm being connected by a fence lever to the lock bolt. Once the fence arm enters the tumbler wheel gates, as is known in the art, the fence lever is released from constraining means to facilitate withdrawal of the lock bolt by further rotation of the dial and its associated shaft. The manipulation of the lock bolt between locking and unlocking positions may be accomplished in response only to rotation of the associated dial and shaft or, as disclosed in U.S. Pat. No. 4,541,259, may be biased toward a locking position when the dead bolt is operated instead as a spring bolt. However, in said '259 patented lock, the dead bolt, whether operated as a true dead bolt or as a spring bolt, does not cooperate with the lock mechanism in any manner to scramble the alignment of the tumbler wheels when the lock is returned to its lock position. It is thus possible in prior combination lock constructions to close a safe door, security door or other structure to be protected by such a lock and, unless the dial is turned to scramble the tumbler wheels, the lock remains in an unlocked condition. This can be particularly a problem where in commercial establishments, staff do not wish to go through the trouble of entering a combination and prefer to close a safe or other security door in an apparently locked condition but do not turn the dial to scramble the tumblers to cause the lock to achieve a truly locked condition. Because of the possibility of such intentional, as well as many unintentional, failures to cause complete locking of a dead bolt combination lock having a plurality of tumbler wheels as discussed hereinbefore, it is the primary object of the present invention to disclose and provide an improved self locking and self scrambling combination lock.

In view of the foregoing, it is primary object of the present invention to disclose and provide an automatically self locking and self scrambling combination lock wherein a plurality of tumbler wheels are employed which have individual tumbler wheel gates which are aligned to one another during the unlocking sequence of manipulation of the lock. It is a further object of the present invention to disclose and provide such a self locking and self scrambling combination lock which is easily manufactured and reliably operated in the same manner as prior similar combination locks but which produces automatically the self locking and self scrambling features noted with a minimum of additional mechanisms or alterations to prior lock constructions.

Generally stated, the present invention in an automatically self locking and self scrambling combination lock includes the provision of a spring biased bolt moveable by its bias t a locking position, a fence lever associated with such spring bias bolt for moving it against such bias to an unlocking position and a plurality of tumbler wheels, each having a fence receiving gate, whereby a predetermined manipulation of the tumbler wheels in accordance with a predetermined combination is required to align the gates, allow the fence lever to enter the gates and thereafter allow manipulation of the lock to withdraw the bolt. The lock thus being automatically self locking; tumbler engaging means are associated with the fence lever for moving one of the aligned tumbler wheels relative other ones thereof to scramble the alignment of the wheels in response to movement of the fence lever as it is withdrawn from the gates under the bias of the bolt moving to its locking position.

More specifically, the present invention in automatic self locking and self scrambling combination lock as aforedescribed includes a detent as part of the tumbler engaging means which is provided upon the fence arm for engaging an edge of one of the gates of one of the tumbler wheels as the arm exits from such gate. An additional spring is provided to urge the fence lever to move outwardly of the gate as the bias of the bolt moves the bolt and associated fence lever toward the bolt locking position and a constraint is provided against which the lever operates within a predetermined arcuate movement as it is biased outwardly of the gate by the additional spring and pulls the gate and wheel in a rotational motion thereof as the bolt is biased toward its locking position.

As a further feature of the within invention, a multiple arm spring member is pivotally mounted to a stationary mounting associated with the lock, has a pair of first and second spring arms associated with the fence lever for biasing it toward and away from the tumbler wheels and a follower arm provided in the path of rotation of a roller actuator mounted to a cam disc fixed to an inner end of the lock shaft rotated by manipulation of a dial associated with the lock. The first spring arm biases the fence lever toward the gates of the tumbler wheels when the roller actuator pivots the spring member toward a deflected position which is resisted by an integral third spring arm thereof which abuts apportion of the lock housing. The second spring arm normally biases the fence lever away from the gates of the tumbler wheels when the spring member is not in the deflected position. Once on each rotation of the dial and its associated shaft, the roller actuator deflects the spring member and biases the fence lever toward to the tumbler wheel gates, release of the spring member by the actuator allowing the spring member to then bias the lever away from the tumbler gates, a feature which is particularly important in the self scrambling feature of the lock as described hereinbefore.

As a still further feature of the present invention the roller actuator, mounted on a cam disc associate with the dial shaft, is constructed of a roller rim eccentrically mounted about a support pin which itself is mounted eccentrically of the center of rotation of the cam disc. Once on each rotation of the dial and lock shaft, when the roller actuator engages the spring member, and specifically a follower arm formed integrally thereof, the eccentrically mounted roller rim moves slightly relative to its circular post mounting. Thus, the timing of the engagement between the roller actuator and the spring member follower arm varies minutely and variably on successive rotations of the dial and lock shaft in a manner to enhance the anti-manipulation characteristics of the lock.

A more complete understanding of the present invention in an automatically self locking and self scrambling combination lock, as well as the realization of additional objects and advantages thereof, will be afforded to those skilled in the art from a consideration of the following detailed description of a preferred exemplary embodiment thereof. Reference will be made to the appended sheets of drawings which will be first briefly described.

FIG. 1 is a plane view of an exemplary embodiment of automatic self locking and self scrambling combination lock, with portions of the rear cover removed, according to the present invention.

FIG. 2 is a section view through the exemplary embodiment of lock of FIG. 1 taken therein along the plane II--II.

FIG. 3 is a detailed vie of a portion of the lock of FIG. 1 showing the exemplary fence lever received within gates of exemplary tumbler wheels as occurs during an unlocking manipulation of the lock.

FIG. 4 is a view as in FIG. 3 showing the tumbler wheels, fence lever and bolt moved to an unlocking position.

FIG. 5 is a detailed view of a portion of the exemplary tumbler wheels and fence lever of FIGS. 1 through 4 showing the associated fence arm engaging sides of the gates of the exemplary tumbler wheels during a locking motion of the bolt.

FIG. 6 is a view as in FIG. 5 showing the release of the fence arm from some of the gates while a detent provided on the fence arm engages a side wall of one of the gates of one of the tumbler wheels in order to scramble its orientation relative the other tumbler wheels as the fence arm is withdrawn from the gates.

FIG. 7 is a vertical section view through the fence arm and tumbler wheels of FIG. 6 taken therein along the plane VII--VII.

FIG. 8 is a view as in FIGS. 5 and 6 showing the fence arm and associated detent moving said one of said tumbler wheels into a scrambled position out of alignment with the other tumbler wheels.

Referring now to FIGS. 1 and 2 initially, an exemplary embodiment of automatically self locking and self scrambling combination lock, in accordance with the present invention, will now be described in detail.

As seen in FIGS. 1 and 2, the exemplary lock is provided with a lock housing, indicated generally at 10 which comprises a box like base 11 which is normally closed by cover plate 12, the latter being secured to base 11 by appropriate fasteners 13 and 14 which may be simple machine screws. Base 11 has a bottom wall 15 and a surrounding side wall 16. The lock mechanism as subsequently described is enclosed within the housing thus provided. The housing is preferably mounted on the inside of a security door or safe door by means of mounting screws, such as screws 17, 18 and 19 as seen in FIGS. 1 and 2. The security or safe door 20 may be provided with a hardened plate 21 as is known in the industry, inwardly of the door to protect the lock against drilling etc. As seen in FIG. 2, a lock shaft 21 is provided in conventional manner for mounting a combination lock dial and extends through the bores 22 and 23 through the door 20 and hardened plate 21 where it passes through the rear wall 15 of lock housing base 11 to mount a plurality of tumbler heels, indicated generally at 30.

The exemplary tumbler wheels, indicated generally at 30, may be provided as disclosed in U.S. Pat. No. 4,142,388, entitled "TUMBLER WHEELS FOR COMBINATION LOCKS" issued to Peter J. Phillips on Mar. 6, 1979 and/or as disclosed in prior U.S. Pat. No. 4,541,259 entitled "COMBINATION LOCK" which issued to Tim M. Uyeda on Sept. 17, 1985. As is now well known in the industry such tumbler wheels are manipulated through rotation of lock shaft 21 in order to enter a predetermined lock combination, the tumbler wheels being provided with individual gates, as tumbler wheel gates 34, 35 and 36 in the tumbler wheels 31, 32 and 33 respectively. When the gates 34, 35 and 36 are aligned, a fence arm 4 may enter the same to allow the nose 41 on fence lever 42 to enter cam slot 37 on cam disc 38, the latter being fixed by stake 39 to a reduced diameter stub shaft 24 which is an extension of shaft 21. Rotation of shaft 21 with fence lever nose 41 in slot 37 facilitates opening the bolt as will know be described.

The lock bolt 50, as seen in FIGS. 1 and 2 is mounted for sliding movement inwardly and outwardly of the lock housing via the channel shaped upper and lower guides 51 and 52, the lower guide being interrupted into two parts 52a and 52b to facilitate assembly of the lock bolt and its associated components. Fence lever 22 is provided with connecting means to the bolt for a pivotal connection therebetween, the exemplary embodiment comprising the retainer screw 53 which pivotally holds the lower end of lever 42 to a side of bolt 50 in known manner.

As a feature of the present invention, the bolt 50, which in normal combination lock situations comprises a dead bolt which is thrown only through manipulation of the lock shaft 21, is provided with a bias which normally urges it toward the locking position of FIGS. 1 and 2. In the exemplary embodiment, such bias is provided by the springs 54 and 55 which have their opposite ends set in appropriate bores provided in the housing web 25 and bolt 50 as seen in the drawings. In the present exemplary embodiment of lock, therefor, as opposed to normal dead bolt lock mechanisms of the prior art, the bolt 50 is biased toward a locking position.

As is particularly contemplated within the present invention, tumbler engaging means are associated with the fence lever for moving one of the aligned tumbler wheels relative other ones thereof to scramble the alignment of the tumbler wheels in response to movement of the fence lever as it is drawn along under the bias of bolt 50 toward its lock position of FIGS. 1 and 2 as will now be described.

In order to open the lock, the tumbler wheels 31, 32 and 33 must be manipulated through successive opposite rotational movement of shaft 21, in a manner known in the industry, to leave the tumbler wheels in selected locations wherein each of the gates 34, 35 and 36 are aligned to one another. Biasing means, as subsequently described, normally urge fence lever 42 toward the tumbler wheels so that when the gates are aligned the fence arm 40 enters the gates as seen in FIG. 3. Rotation of shaft 21 and its associated stub shaft 24 rotates the cam disc 38 counterclockwise in FIGS. 3 and 4 to draw fence lever by its nose 41 under the constraining means 60, the latter having constraining surface 61 which is normally engaged by lever end surface 43 to prevent opening of the lock bolt until the fence lever 40 is received within the gates, as seen in FIG. 1. As seen in FIG. 4, movement of fence lever 42 under constraining means 60 withdraws bolt 50 from the receptacle 56 which may be part of safe door jam, security door jam or the bolt works within a security or safe door which in turn operates door bolts.

In the exemplary embodiment, the tumbler engaging means for scrambling one of the tumbler wheels relative the others during locking movement of the bolt 50 includes the provision of a detent 70 as best seen on FIG. 7, on an end of fence ar 40. As seen in section in FIG. 5, fence arm 40 may have a semi-circular configuration as indicated at 71 in FIG. 5 as it extends from lever 42 and have a full circular cross-section as indicated at 72 at its outer end to provide the detent 70. As seen in FIG. 5, as fence arm 40 is raised by a spring bias, as subsequently described, during a bolt locking motion the half circular portion 71 of arm 40 clears the edges of gates 35 and 36 as seen in FIGS. 6 and 7 before the detent 70 clears the last gate 34 of tumbler wheel 31 as seen in FIG. 8, such continued engagement moving tumbler 31 relative tumbler wheels 32 and 33 to scramble the relative alignment thereof during the locking motion of bolt 50 and the associated fence lever 42 as seen in FIGS. 5 through 8. As is also seen in FIGS. 5 through 8, the constraining means 60 limits movement of the lever 42 and consequently detent 70 to ensure engagement between detent 70 and gate 34 of tumbler wheel 31 as seen in FIG. 6 due to the constraint of cam surface 61 against lever end surface 43 as seen in FIG. 6.

In order for the fence lever 42 to be alternately biased toward the tumbler wheels during the bolt unlocking movement from FIG. 1 to FIG. 4 and to be biased away from the tumbler wheels during the bolt locking movement as the bolt moves from the position of FIG. 4 back to FIG. 1, and the detent 70 engages gate 34 of tumbler wheel 31 under the constraining action of constraining means 60 as seen in FIGS. 5 through 8, and as is also particularly contemplated within the scope of the present invention, improved biasing means are provided for effecting the aforestated bias upon lever 42 and lever arm 40 as now will be described in detail.

In the exemplary embodiment, such biasing means is provided by a multiple arm spring member, indicated generally at 80, which is pivotally mounted by pin 81 to mounting boss 82 provided integrally of housing base 11 as seen in FIGS. 1 through 4. A first spring arm 83 provides an additional spring means for urging the fence lever 42 and fence arm 40 toward the tumbler wheels when bolt 50 is in the locking position of FIGS. 1 and 2, spring arm 83 normally riding on top of the abutment pin 45 provided on a lever 42. A second spring arm 84 is provided as an integral part of the spring member, indicated generally at 80, which, as seen in FIGS. 1 through 4, underlies abutment pin 45 on the fence lever 42 to provide an additional spring means, in addition to springs 54 and 55, for urging the fence lever 42 to move the fence arm 40 outwardly of the gates 34, 35 and 36 as the bolt is moved by the bias of springs 54 and 55 toward a bolt locking position as seen in FIGS. 1 and 2. Spring arm 84, and its additional spring means thus provided, is important to lift the fence arm 40 out of the gates as the bias of bolt 50 moves the lever from below the constraining means 60 as seen in FIG. 4 to the position of FIG. 5. Moreover, the presence of spring 84 urges the fence arm 40 to move in a constrained arcuate movement upwardly along the surface 61 of the constraining means 60 as the bolt moves to its locking position to first leave the gates 35 and 36 and then drag detent 70 across the corner of the top edge of gate 34 as seen in FIG. 8 to scramble the tumbler wheels.

The spring arms 83 and 84 are provided to normally lie in parallel spaced relation on opposite sides of abutment pin 45 as seen in FIG. 1. In order to actuate the bias of upper arm 83, a roller actuator, indicated generally at 90 is mounted on cam disc 38 to revolve with and eccentrically of stub shaft 24 as the lock shaft 21 is rotated. Once upon each rotation of shaft 21, and its associated stub shaft 24, the roller actuator indicated generally at 90, comes into engagement with the follower arm 85 which is formed integrally of the multiple arm spring member indicated generally at 80. As seen from a comparison of FIGS. 1 and 3, rotation of shafts 21 and 24 causes the actuator roller, indicated generally at 90, to engage actuator arm 85 and deflect the spring member to cause the upper spring arm 83 to bias the fence lever 42 and its fence arm 40 toward the tumbler wheels and tumbler wheel gates as seen in FIG. 3 once upon each rotation of shafts 21 and 24. This deflective movement of the multiple arm spring member, indicated generally at 80, is resisted by a third integral spring arm 86 which, as seen in FIGS. 1, 3 and 4 is provided to abut against an inner surface of housing side walls 16 to normally position the spring member, indicated generally at 80, in a normal position of rest as seen in FIG. 1. Once upon each rotation of shafts 21 and 24 in either direction, the roller actuator, indicated generally at 90, causes the spring member, indicated generally at 80, to deflect to the deflected position of FIG. 3 to bias the lever 42 and its lever arm 40 toward the tumbler wheels and gates as discussed.

As is also particularly contemplated within an aspect of the present invention, the timing of the engagement between the roller actuator, indicated generally at 90, and the follower arm 85 of the multiple arm spring member is adjusted through the provision of a roller rim 91 which is mounted by an eccentrically formed bore 92 by which rim 91 is rotatably mounted to circular mounting pin 93. Upon each engagement between roller rim 91 and actuator arm 85, the ri 91 moves in a rotational motion in small random increments relative mounting post 93. Since the thickness of rim 91 relative the post 93 varies about the circumference of the mounting post 93 due to the eccentric mounting of rim 91 to post 93, the exact point of contact between the roller rim 91 and actuator arm 85 on successive rotations of lock shaft 21 and its associated stub shaft 24 vary from rotation to rotation. There is thus an advantage in the anti-manipulation aspects of the present lock in providing for a variation in a random manner of the timing of the engagement of the roller actuator with the follower arm to operate the fence lever toward the tumbler wheels and the associated tumbler wheel gates on successive rotations of the lock shaft.

Having thus described a preferred exemplary embodiment of an automatically self locking and self scrambling combination lock in accordance with the present invention, it should now be apparent to those skilled in the art from a consideration of the foregoing that various advantages and objects have been attained and enhanced lock security afforded by the within invention which is limited only by the following claims.